the cd player?

the laser lens is dirty or the laser power has reduced.First if you can see the laser lens through the front of the unit(this is the small glsss looking object)use a cotton bud wrapped to a pencil,so that you have length to reach in and touch the top of the laser,the cotton bud can be soaked in one of the many audio cleaning fluids.Move the cotton bud over the lens a few times and then try playing your cd again.If this fails you require the laser assy/mech replaced(over my service years i have replaced 100s of lasers for this type of problem)

Tom
June 2010